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mirror of synced 2024-12-03 19:57:20 +01:00
ImHex/lib/libimhex/source/pattern_language/preprocessor.cpp
2022-02-01 22:09:44 +01:00

245 lines
10 KiB
C++

#include <hex/pattern_language/preprocessor.hpp>
#include <hex/helpers/fmt.hpp>
#include <hex/helpers/paths.hpp>
#include <hex/helpers/file.hpp>
#include <filesystem>
namespace hex::pl {
std::optional<std::string> Preprocessor::preprocess(const std::string &code, bool initialRun) {
u32 offset = 0;
u32 lineNumber = 1;
bool isInString = false;
if (initialRun) {
this->m_defines.clear();
this->m_pragmas.clear();
}
std::string output;
output.reserve(code.length());
try {
bool startOfLine = true;
while (offset < code.length()) {
if (offset > 0 && code[offset - 1] != '\\' && code[offset] == '\"')
isInString = !isInString;
else if (isInString) {
output += code[offset];
offset += 1;
continue;
}
if (code[offset] == '#' && startOfLine) {
offset += 1;
if (code.substr(offset, 7) == "include") {
offset += 7;
while (std::isblank(code[offset]) || std::isspace(code[offset]))
offset += 1;
if (code[offset] != '<' && code[offset] != '"')
throwPreprocessorError("expected '<' or '\"' before file name", lineNumber);
char endChar = code[offset];
if (endChar == '<') endChar = '>';
offset += 1;
std::string includeFile;
while (code[offset] != endChar) {
includeFile += code[offset];
offset += 1;
if (offset >= code.length())
throwPreprocessorError(hex::format("missing terminating '{0}' character", endChar), lineNumber);
}
offset += 1;
fs::path includePath = includeFile;
if (includeFile[0] != '/') {
for (const auto &dir : hex::getPath(ImHexPath::PatternsInclude)) {
fs::path tempPath = dir / includePath;
if (fs::exists(tempPath)) {
includePath = tempPath;
break;
}
}
}
File file(includePath, File::Mode::Read);
if (!file.isValid())
throwPreprocessorError(hex::format("{0}: No such file or directory", includeFile.c_str()), lineNumber);
bool shouldInclude = true;
this->addPragmaHandler("once", [&, includePath, this](const std::string &value) {
auto [iter, added] = this->m_onceIncludedFiles.insert(includePath);
if (!added) shouldInclude = false;
return value.empty();
});
auto preprocessedInclude = this->preprocess(file.readString(), false);
if (!preprocessedInclude.has_value())
throw this->m_error;
if (shouldInclude) {
auto content = preprocessedInclude.value();
std::replace(content.begin(), content.end(), '\n', ' ');
std::replace(content.begin(), content.end(), '\r', ' ');
output += content;
}
} else if (code.substr(offset, 6) == "define") {
offset += 6;
while (std::isblank(code[offset])) {
offset += 1;
}
std::string defineName;
while (!std::isblank(code[offset])) {
defineName += code[offset];
if (offset >= code.length() || code[offset] == '\n' || code[offset] == '\r')
throwPreprocessorError("no value given in #define directive", lineNumber);
offset += 1;
}
while (std::isblank(code[offset])) {
offset += 1;
if (offset >= code.length())
throwPreprocessorError("no value given in #define directive", lineNumber);
}
std::string replaceValue;
while (code[offset] != '\n' && code[offset] != '\r') {
if (offset >= code.length())
throwPreprocessorError("missing new line after #define directive", lineNumber);
replaceValue += code[offset];
offset += 1;
}
if (replaceValue.empty())
throwPreprocessorError("no value given in #define directive", lineNumber);
this->m_defines.emplace(defineName, replaceValue, lineNumber);
} else if (code.substr(offset, 6) == "pragma") {
offset += 6;
while (std::isblank(code[offset])) {
offset += 1;
if (code[offset] == '\n' || code[offset] == '\r')
throwPreprocessorError("no instruction given in #pragma directive", lineNumber);
}
std::string pragmaKey;
while (!std::isblank(code[offset]) && code[offset] != '\n' && code[offset] != '\r') {
pragmaKey += code[offset];
if (offset >= code.length())
throwPreprocessorError("no instruction given in #pragma directive", lineNumber);
offset += 1;
}
while (std::isblank(code[offset]))
offset += 1;
std::string pragmaValue;
while (code[offset] != '\n' && code[offset] != '\r') {
if (offset >= code.length())
throwPreprocessorError("missing new line after #pragma directive", lineNumber);
pragmaValue += code[offset];
offset += 1;
}
this->m_pragmas.emplace(pragmaKey, pragmaValue, lineNumber);
} else
throwPreprocessorError("unknown preprocessor directive", lineNumber);
} else if (code.substr(offset, 2) == "//") {
while (code[offset] != '\n' && offset < code.length())
offset += 1;
} else if (code.substr(offset, 2) == "/*") {
while (code.substr(offset, 2) != "*/" && offset < code.length()) {
if (code[offset] == '\n') {
output += '\n';
lineNumber++;
}
offset += 1;
}
offset += 2;
if (offset >= code.length())
throwPreprocessorError("unterminated comment", lineNumber - 1);
}
if (code[offset] == '\n') {
lineNumber++;
startOfLine = true;
} else if (!std::isspace(code[offset]))
startOfLine = false;
output += code[offset];
offset += 1;
}
if (initialRun) {
// Apply defines
std::vector<std::tuple<std::string, std::string, u32>> sortedDefines;
std::copy(this->m_defines.begin(), this->m_defines.end(), std::back_inserter(sortedDefines));
std::sort(sortedDefines.begin(), sortedDefines.end(), [](const auto &left, const auto &right) {
return std::get<0>(left).size() > std::get<0>(right).size();
});
for (const auto &[define, value, defineLine] : sortedDefines) {
i32 index = 0;
while ((index = output.find(define, index)) != std::string::npos) {
output.replace(index, define.length(), value);
index += value.length();
}
}
// Handle pragmas
for (const auto &[type, value, pragmaLine] : this->m_pragmas) {
if (this->m_pragmaHandlers.contains(type)) {
if (!this->m_pragmaHandlers[type](value))
throwPreprocessorError(hex::format("invalid value provided to '{0}' #pragma directive", type.c_str()), pragmaLine);
} else
throwPreprocessorError(hex::format("no #pragma handler registered for type {0}", type.c_str()), pragmaLine);
}
}
} catch (PatternLanguageError &e) {
this->m_error = e;
return std::nullopt;
}
return output;
}
void Preprocessor::addPragmaHandler(const std::string &pragmaType, const std::function<bool(const std::string &)> &function) {
this->m_pragmaHandlers[pragmaType] = function;
}
void Preprocessor::addDefaultPragmaHandlers() {
this->addPragmaHandler("MIME", [](const std::string &value) {
return !std::all_of(value.begin(), value.end(), isspace) && !value.ends_with('\n') && !value.ends_with('\r');
});
this->addPragmaHandler("endian", [](const std::string &value) {
return value == "big" || value == "little" || value == "native";
});
this->addPragmaHandler("once", [](const std::string &value) {
return value.empty();
});
}
}